Carburetor



Aug. 23, 1932. F. c. MOCK ET AL CARBURETOR Original Filed April 24, 1923Patented Aug. 23, 1932 UNITED STATES PATENT OFFICE FRANK C. MOCK,CHARLES J. GUSTAFSON, AND MILTON E. CHANDLER, OF CHICAGO,

ILLINOIS, ASSIGNORS TO IBENDIX STROMBERG CABBURETOR COMPANY, OFCHICAGO,-

ILLINOIS, A CORPORATION OF ILLINOIS CARBURETOR Application filed April24, 1922, Serial No. 556,160, and in Great Britain September 6, 1919.Renewed April 2, 1930.

The present invention relates to improvements in carburetors, and is acontinuation in part of our co-pending Patent No. 1,620,- 827, for whichthe application was filed July 10, 1918.

One of the particular objects of the invention is to provide a fuelnozzle so related to the carburetor structure that the port openingthereof can be moved or shifted, as for the purpose of bringing the portunder a greater or lesser degree of suction influence.

A further object is to provide a particular arrangement of nozzle forcarrying the above object into effect, this nozzle being preferably inthe form of an adjustable plug or the like separate from the body of thecarburetor.

In the present form, which is merely illustrative, the invention isembodied in the conventional type of idling device which is generallyemployed in plain tube carburetors and which is usually arranged todischarge in the immediate vicinity of the throttle. It is well knownthat in such carburetors there is an extremely Wide variation of suctionon the main nozzle. The performance of an airplane carburetor istypical, the suction on the main nozzle varying approximately as the 6thpower of the engine speed under the pro peller load. From approximatelyone-half speed down there is generally not enough suction on the mainnozzle to accurately meter the mixture. Consequently, duringthisrangethe point of feed must be from the idling nozzle above or at the upperedge of the throttle. From this it will be noted that during aconsiderable part of the running period, and over a considerable portionof the range of speeds, the idling nozzle is the primary source of fuelsupply and should, therefore, meter the proportions with substantiallythe same degree of accuracy required of the customary main nozzle. Thecontrol of speed during this portion of the range is obtained by acomparatively small movement of the throttle, which requires that theidling nozzle be located with certain exactness relative to the throttleto accurately control the range of suction at this nozzle during thiscomparatively small movement. Added to this is the further diflicultythat the suction above the throttle diminishes with the movement ofopening the throttle owing to the greater volume of air admitted. Thisis the direct converse of what is desired at the idling nozzle, becauseduring this time a higher suction is desirable at the nozzle for drawingthe increased amount of fuel required for the greater volume of air.During the operation of the throttle, there should be a gradualtransition or blending from the operation of one nozzle to the operationof the other, otherwise lean charges or charges of pure air may beadmitted owing to the idling nozzle diminishing or discontinuing itsfeed before the main nozzle takes up operation. Hence, the idling nozzleshould be capable of feeding an increased volume of fuel during acertain range of the throttle movement, despite the lowering of thesuction above the throttle.

This, or practically any other variation of idling nozzle feed can besecured by utilizing differentially the relatively high suction existingabove the throttle and the relatively low suction existing below it. Forexample, only a small portion of the nozzle opening may be subjected tothe suction above the throttle during very slow running, and with theopening movement of the throttle a greater portion of the nozzle openingmay be subjected to the higher suction above the throttle. Theconfiguration of the nozzle opening may be such that for a given enginespeed a certain proportion of the nozzle opening will be subjected tosuction above the throttle and a certain proportion to the suction belowthe throttle. Shifting of the throttle towards an open positionincreases the proportion of nozzle opening subjected to suction abovethe throttle and decreases the proportion of nozzle opening exposed tosuction below the throttle.

It will be apparent that to obtain this accurate control of the idlingnozzle feed a very accurate location of the nozzle relative to thethrottle is essential. In the case of the ordinary butterfly throttle,when the throttle is in a closed or restricted position its edgecontacts or moves toward the wall of the carburetor barrel on an angleclosely approaching a tangent. Consequently, any variation of evenminute degree in the bore of the carburetor will result in the throttleedge contacting with the carburetor wall at a higher or lower pointalong the length of the wall. To take care of this condition it isnecessary that relative adjustment be afforded between the throttle andidling nozzle, if accuracy of mixture proportion is to be obtained.

In the present construction, and as broadly disclosed in our abovementioned patent, we have provided an arrangement of idling nozzle whichcan be moved relative tothe carburetor casting, preferably by rotationof the nozzle, so as to selectively dispose the nozzle openings indifferent positions relative to the edge of the throttle. Thus, thenozzle opening can be moved to withdraw it or a portion thereof from theinfluence of' the suction above the throttle, or to increase the area ofnozzle opening subjected to this higher suction, or to confine a greateror less extent of the nozzle opening to the differential suctionexisting at the lip of the throttle. This conception-of an idling nozzleadjustable with respect to the influence of suction thereon, has thefurther possibility of permitting the nozzle opening to be shiftedlongitudinally of the valve, as we have above stated, for the purpose ofincreasing the area of nozzle opening subjected to the suction of oneside of the throttle and decreasing the area of nozzle opening subjectedto the suction of the other side of the throttle.

This conception of an adjustable idling nozzle has convenient and simpleadaptation in the form of a plug which seats in an opening in thecarburetor body and is removable for convenient substitution andadjustment. By inserting the plug at different angles or rotating it tothese angles, the port opening can be disposed in any desired positionrelative to the edge of the throttle. This port opening may be of suchconfiguration and so located in the plug that the angular adjustment ofthe plug will raise or lower the opening relative to the throttle ordispose different areas of port opening above or.

below the throttle. A closure plug is preferably employed to close theouter end of the opening in which the idling plug is seated, thisclosure plug holding the idling plug In any of its various positions ofadjustment and closing the outer end of the aforesaid opening in whichthe nozzle plug is disposed. While this is the preferred manner ofaccomplishing the objects set out above, it will be obvious that thesame can be accomplished by other arrangements of the jet. In thedrawing illustrating the present embodiment:

Figure 1 is a fragmentary sectional view of a carburetor embodying ourinvention, illustrating the relation of nozzle plug and closure plugdisclosed in our Patent 1,620,827.

Fig. 2 is a fragmentary sectional view on an enlarged scale of amodified construction, and Fig. 3 is an elevational view of the face ofthe nozzle plug as viewed from the interior of the carburetor barrel,the position of the throttle across the plug being shown to illustratethe manner of adjustment of the plug.

Figs. 4 and 5 are views similar to Figs. 2 and 3, but showing a modifiedconstruction of plug.

Figs. 6 and 7 are views similar to Figs. 2 and 3 showing a modifiedconstruction of plug wherein the nozzle opening is formed by milling oneside of the plug away; and

Figs. 8 and 9'are views similar to Figs. 2 and 3 of still anothermodified construction of plug.

The particular form of carburetor illustrated in Figure 1 is selectedfor illustrating a typical embodiment simply because it forms the.subject-matter of our above mentioned patent; it being obvious that thepresent invention is capable of embodiment in practically any type ofcarburetor. A specific description of this carburetor being available insaid patent, sufiice it to say here that it comprises a body portion orcasting 15, having an air intake 16 and a mixture outlet 17. A throttle18 controls the mixture outlet 17, and a main nozzle 19 discharges intothe innermost of two concentric venturis 21 and 22. The idling nozzle,which is designated 23 in its entirety, discharges into the mixturepassageway 20 in close proximity to the edge of the throttle 18. Thisidling jet draws'fuel thru a tube 24, which is secured at its lower endin a plug 25, the tube having a lateral hole 26 which also extends thruthe plug for admitting fuel to the tube. Fuel is supplied to both themain jet and idling jet from a float chamber 27 which discharges thru apassageway 28 into the center of the main nozzle 19 and into anaccelerating well 29 surrounding said nozzle. The idling nozzle 23 drawsfrom this accelerating well thru a passage 31.

Referring to the particular construction of the idling nozzle, it willbe noted that the nozzle is-arranged in a relatively large hole which isformed to extend thru the side wall of the casing 15 adjacent the pointwhere the lower lip of the throttle 18 comes into approximate contactwith the side wall of the passageway 20 when the throttle is in itsrestricted position. This bore 32 has an enlarged counterbore 32' whichis threaded at its outer end. Fitting in this bore is a nozzle plug 33having reduced portions extending into the bore 32 and counterbore 32'and an enlarged flanged portion seating against the inner end of thecounterbore 32. This plug is backed up and held in any position in whichit may be adjusted by a threaded closure plug 34 which screws into thethreads in the end of the counterbore 32' and abuts the rear end of thenozzle plug 33. The nozzle plug 33 has a transverse hole 35 whichcommunicates by way of the slot 36 with the mixture passageway 20, thisslot 36 lying in proximity to the lip of the throttle valve 18 when thesame is in closed or restricted position. The plug 33 has a bore 37 thruwhich the fuel mixture for idling passes on its way into the enginemanifold. The plu has a lateral recess 38 lying immediately above thetube 24, which tube may have a plug restriction 39 in its upper end ifdesired. A channel or annular space 41 is formed about the outer end ofthe plug 33, this channel or annular space forming an air space for airwhich is admitted by way of the port 42, valve port 43, and radial port44 in the plug 34.

A needle valve 45 is threaded into the hub of the plug 34 forcontrolling the amount of air which enters by way of the port 42,- whichair in connection with that passing through slot 36 and the liquid fuelentering from the tube 24 forms a mixture for supplying the engineduring idling. This needle valve comprises a suitable cylindrical stemwhich is threaded to fit within the boss extension on the end of theplug 34, and has a slot or other suitable means for applying anadjusting tool, such as a screw driver. This valve member has adiametrical hole near the end of the same, a spring 46 and a pair ofspherical rollers 47 lying in said bore. The interior of the hubextension on the end of the plug 34 is provided with a seriesoflongitudinal grooves into which the rollers 47 tend to seat under theinfluence of spring 46. This to hold the rollers 47 and thus the valve45 against movement. The plug 34 has an extending flange 49 havingaperture 51 thru which a releasable wire clip 52 may cc extended forpreventing rotation'of the plug 34 after the same has been screwed intoposition.

When the throttle 18 is in its restricted position with the lower lipthereof substantially intersecting the slot 36, as shown, it will beapparent that a certain rate of fuel feed will occur thru the slot 36depending upon the suction above the throttle, the suction below thethrottle and the velocity of air around the throttle lip thru the slot36. It will be observed'that by turning the plug 33, a greater or less:area of the slot 36 is brought into alignment with the lower lip of thethrottle.

This brings a greater or lesser proportion of the slot area under theinfluence of the suction existing around the edge of the throttle. Thus,by changing the angle of the plug 33 and its slot 36, different rates offuel feed can be obtained. The channel or annular space 41 maintainscommunication with the upper end of the tube 24, or rather therestricted plug 39, so that fuel flow will be maintained even though theplug 33 is adjusted thru a wide angle. The separate mounting of the plug33 in the casting obviously permits of this adjustment with littledifficulty, and after the plug has been properly adjusted it is securedfirmly in position by screwing the closure plug 34 hard against it.

This practice of making the idling nozzle in a separate plug alsopossessestlie advantage that the plugs may be easily substituted forplugs having larger or smaller or diflerently shaped orifices. Thus, bya simple removel of the outer plug 34, the nozzle plug 33 may be removedand a plug having a larger or smaller or differently formed fuel openingmay be quickly substituted.

In Figures 2 and 3 we have illustrated a modified construction. Heretheadjustable and removable nozzle plug 7 2 is of relatively shallow depthand the fuel passageway 24' enters the plug bore behind the plug 72. Thefuel passes thru a number of holes 55 into the interior of the outerclosure plug 77, from whe'nce it has communication to the slot 73 in thefront of the nozzle plug thru an axial passageway f 5. A needle valve59' controls the passageway 75, this I needle valve having. threadedengagement in the outer end of the plug 77 and having a cap or handle 61secured to its outer end by which the; needle valve may be adjusted. Aspring ball '62 is adapted to bear againstthe inside of the flange onthe cap 61 so as to retain the valve in any adjusted position. Asmallpacking nut 63 is threaded into the open end of the plug 7 7 and holds asuitable packing 64 about the stem- 0f the needle valve 59'.

As described in the previous embodiment, the nozzle plug 72 can beadjusted, as by rotating the same, or the plug may be substituted byplugs having different sized or different shaped apertures for adjustingthe low idling mixture. The reduced cylindrical portion 74 of the nozzleplug 72 may be;

milled around its circumference so that extending diagonally thru theenlarged por tion of the plug. As shown in Figure 2, the fuel passageway24' opens into the annular area 70 surrounding the end of the closureplug 77 Radial holes conduct the fuel into the bore of the closure plugfrom whence it enters the diagonal passage 75 under the control of thevalve 59. By this arrangement the slot 73 remains in communication withthe fuel tube 24' even though the plug 72 is adjusted thru a wide rangeof angular movement. WVhere no air is admitted through the closure plug,a suitable air port is provided to discharge into the passageway 24below the idling nozzle.

' By virtue of the eccentric disposal of the slot 73, it will be notedthat different proportions of effective slot opening may be disposedeither above or below any given position of the throttle by the mererotation of the plug. For example, with a given throttle position suchas shown in Figure 3, it will be observed that by .rotating the plugcounter-clockwise, that proportion of the slot area above the lip of thethrottle may be increased, or the entire slot area may be disposed abovethe lip of the throttle; and conversely, by rotating the plug in aclockwise direction, the greater proportion or the entire area of theslot opening may be disposed below the lip of the throttle. This alsoenables the nozzle opening to be quickly and easily adjusted to take.care of the slight variations in the location of the throttle lip inposition ofclosed throttle. As we have previously remarked, it wouldrequire painstaking and expensive machiningto insure that thethrottlelip of every carburetor ofthe same design would stop atprecisely the same point in the carburetor barrel. The adj ustability ofthe present nozzle plug dispenses with the necessity for accurateconstruction or assembly of the parts, as its wide adjustment is ampleto take care of all variations resulting from mechanical discrepancies.

The proportions of the various idling mixtures can be very convenientlyadjusted by the rotation of this nozzle plug. A higher suction alwaysprevails on the upper side of the throttle during idling than on thelower side, and by rotating a greater or lesser area of the slot openinginto communication. with the higher suction zone above the throttle, orthe lower suction zone below the throttle, practically any desiredimpinging against the bottom ofthe port and the fuel issuing therefrom.It will be apparent that any of the present adjustments disposed belowthe lip of the throttle and the slot above, or vice versa, or the areasof both the port and the slot may be distributed artly above and partlybelow the lip o the throttle. This slot may perform a deflecting ordirecting function for the mixture in the port 78.

In Figures 6 and 7 a portion of the plug is milled oil or cut awaytransversely as indicated at 82. That portionof the plug opening 32which .is thus left void by milling off the plug, constitutes the idlingnozzle. It will be apparent that by rotating the plug this nozzleportion of the plug opening 32 may be shifted to practically any pointaround the circumference of the hole so that the nozzle opening may bedisposed above, below or across the throttle lip in any desired ratio.One such position is indicated in dotted lines.

In Figures 8 and 9 this plug is formed with a port 84 of agenerallycircular form which is disposed eccentric to the plug. Rotationof the plug will dispose this port either above, or below, or straddlingthe lip of the throttle, (the latter as shown In dotted lines) in thesame manner described in the previous embodiments. I

Another modification of the invention is disclosed and claimed inapplicants copending application Serial No. 438,278, filed March 24,1930, which is a continuation in part of this application.

The numerous modifications illustrated are only indicative of the largenumber of methods of carrying the invention into effect. They are alldifferent manifestations of the one generic invention. The appendedclaims have been drawn to the endof covering these various methods ofeffecting the one common invention,and such others as would naturallyoccur to one skilled in the art.

We claim:

1. In a carburetor,the combination of a carbureting chamber havin athrottle valve therein, the wall of said 0 amber having a plug chambertherein, a nozzle plug at the inner end of said plug chamber-having afuel port terminatin in said carbureting chamber adjacent to t e edge ofthe throttle valve when the valve is closed, said nozzle plug beingrotatable whereby its fuel port may be adjusted relative to the throttlevalve, a separate plug threading into the outer end of said plug chamberto abut against said nozzle plug to lock said nozzle plug in adjustedposition, said nozzle plug having a passage leading to said fuel port,and a valve carried by said separate plug for cooperating with the outerend of said passage.

2. In a carburetor, a carbureting chamber having a throttle valvetherein, a sidewall of said chamber having a bore therethrough, thevalve having a lip adapted in substantially closed position to overhangthe said bore, a rotatable idling plug disposed in said bore and havingan idling passageway formed therein, there being a passageway forsupplying liquid fuel to said idling passageway, said idling passagewaybeing eccentric relative tothe axis of said plug for adjustment of theposition of the same under the lip of the throttle to vary the qualityof the mixture of fuel and air supplied by the carburetor by rotation ofsaid plug.

3. In a carburetor, the combination of a mixture passageway, a throttlecontrolling the same, and a fuel port for discharging fuel and airadjacent the lip of said throttle when the latter is in a restrictedposition, the position of said fuel port being adjustable relative .tosaid throttle.

4. In a carburetor, the combination of a carbureting passageway, athrottle controlling flow through said passageway and a fuel port fordischarging fuel and air into said passageway adjacent said throttle,said port being adjustable longitudinally of said passageway.

5. In a carburetor, the combination of a carbureting passageway, athrottle controlling the same, a fuel plug having a port dischargingfuel and air into said passageway adjacent said throttle, said fuel plugbeing rotatable for shifting the location of said port relative to saidthrottle.

6. In a carburetor, the combination of a carbureting passageway, athrottle controlling the same, a nozzle having a nozzle plug dischargingfuel into said passageway adjacent said throttle, said plug beingrotatable for shifting said nozzle longitudinally of said passageway.

7 In a carburetor, the combination of a carbureting chamber, a throttlein said cham her, a fuel passageway arranged to discharge fuel into thecarbureting chamber adjacent the edge of said throttle when the latteris in a restricted position and means for shifting the point ofdischarge of said fuel passageway relative to said throttle.

8. In a carburetor, the combination of a body portion having acarbureting passageway extending therethrough, a plug separate from saidbody portion and disposed in an opening therein, said plug having a fuelport discharging fuel into said passageway and being rotatable to adjustthe location of said port.

9. In a carburetor, the combination of a carbureting chamber having athrottle therein, the wall of said chamber having an aperture thereinadjacent said throttle, an idling nozzle plug in said aperture andhaving a fuel port for discharging fuel and air into said carburetingchamber, said nozzle plug being removable for substitution oradjustment, and a co-operating closure plug behind said nozzle plug.

10. In a carburetor, the combination of a. carbureting chamber having athrottle therein, the wall of said chamber having an aperturetherethrough adjacent said throttle, a fuel nozzle plug in said aperturehaving a port for discharging fuel into said carbureting chamber, saidnozzle plug being rotatable for adjusting the location of said portrelative to said throttle and a cooperating closure plug engaging insaid aperture in back of said nozzle plug.

11. In a carburetor, the combination of a carbureting chamber, a fuelnozzle plug'removably and rotatably mounted to discharge into saidcarbureting chamber, said plug having a fuel port discharging fuel intosaid chamber and disposed eccentrically therein, the rotatableadjustment of said plug oper. ating to shift the location of said port.

12. In a carburetor, the combination of a carbureting chamber having athrottle therein, the wall of said chamber having an aperture extendingtherethrough adjacent said throttle, a nozzle plug seated in saidaperture, said plug having a fuel discharging slot extendingtransversely thereof, and a co-operating closure plug in back of saidnozzle plug.

13. In a carburetor, the combination of a carbureting chamber having athrottle therein, the wall of said chamber having an aperture thereinadjacent said throttle, an idling nozzle plug seated in said aperture, afuel supply passageway extending through the wall of said carburetingchamber and communicating with said plug, said plug having one sidethereof cut off to provide a fuel port discharging from one side of saidplug, said fuel port being shiftable relative to the edge of saidthrottle by the rotation of said plug.

14. In a carburetor, the combination of a cylindrical carburetingpassageway having a throttle valve therein, the wall of said passagewayhaving a plug chamber extending bore in the wall of said chamber adaptedto accommodate one of a plurality of idling nozzle plugs havingdifferent sized fuel orifices for metering and regulating the low idlinmixture, means for supplying air and liqui fuel to said plug, and meansfor shifting the position of said plug in said chamber for regulatingthe high idling mixture.

16. In a carburetor having a carbureting chamber, a main jet nozzle anda throttle valve in said chamber, an idle fuel feed from the interior ofthe main jet nozzle into said chamber through a metering orifice andopenings above and below the edge of said throttle when same is closed,means for adjusting the size of said openings relative to each other,and means for adjusting the fuel feed through said metering orificeincluding an adjustable air vent.

17. In a carburetor, a carbureting chamber having a throttle valvetherein, a radial opening in the side wall of said chamber so located asto be overhung by the lip of said throttle when same is in restrictedposition, a movable idling plug disposed in said opening and having anidling fuel passageway therein, there being a duct for supplying liquidfuel to said idling passageway, said idling passageway being movablealong the side wall of said chamber for adjustment relative to the lipof said throttle to vary the quality of idling mixture supplied by thecarburetor.

In witness whereof, we hereunto subscribe our names this 20th day ofApril, A. D. 1922.

FRANK C. MOCK. CHARLES J. GUSTAFSON. MILTON E. CHANDLER.

